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Calamansi or Philippine lime (Citrofortunella macrocarpa) is an important crop for local economic in Hainan Island. There is no study about Calamansi germplasm evaluation and cultivar development. In this study, Calamansi data were collected from 151 of Calamansi seedling trees, and 37 phenotypic traits were analyzed to investigate their genetic diversities. The cluster analysis and principal component analysis were conducted aiming to provide a theoretical basis for the Calamansi genetic improvement. The results of the diversity analysis revealed: (1) the diversity indexes for qualitative traits were ranged from 0.46–1.39, and the traits with the highest genetic diversity level were fruit shaped and pulp colored (H′ > 1.20); and the diversity indexes for quantitative traits ranged from 0.67–2.10, with the exception of a lower in fruit juice rate (1.08) and lower in number of petals (0.67). (2) The clustering analysis of phenotypic traits have arranged the samples into 4 categories: the first group characterized by fewer flesh Segment number per fruit (SNF) and more Oil cell number (OCN); the second group had 7 samples, all characterized with larger Crown breadth (CB), higher Yield per tree (YPT), the lager leaf, the higher Ascorbic acid (AA), and less Seed number per fruit (SNPF); the third group had 25 samples characterized by smaller Tree foot diameter (TFD),smaller Fruit shape index (FSI) and higher Total soluble solids (TSS) contain; the fourth group had 87 samples, they were characterized by shorter Petiole length (PEL), larger fruit, higher Juice ratio (JR), multiple Stamen number (SN) and longer Pistil length (PIL). (3) The principal component analysis showed the values of the first 9 major components characteristic vectors were all greater than 3, the cumulative contribution rate reach 72.20%, including the traits of single fruit weight, fruit diameter, tree height, tree canopy width etc. Finally, based on the comprehensive main component value of all samples, the Calamansi individuals with higher testing scores were selected for further observation. This study concludes that Calamansi seedling populations in the Hainan Island holds great genetic diversity in varies traits, and can be useful for the Calamansi variety improvements. [ABSTRACT FROM AUTHOR]

The fast-growing coastal aquaculture industry provides nutritious seafood and huge wealth for society, but also affects the natural environment and coastal ecosystems. There is an urgent need to realize the sustainable development of coastal aquaculture with regard to the trade-off between economic development and ecological conservation. Satellite remote sensing provides long-term data on the distribution and dynamics of aquaculture, which is essential for the design of suitable policy interventions for sustainable development. In this study, Landsat time series were used to map the tendencies and dynamics of aquaculture ponds for 30 years (1987–2018) in the coastal area of Hainan Island, China. The results showed that (1) the coastal aquaculture area of Hainan Island first increased rapidly, then increased slowly, and then decreased slightly in the past 30 years, increasing by approximately 10 times. The largest annual change rate of aquaculture ponds was between 2000 and 2005 (1597 ha/year), followed by the period 1995–2000 (1414 ha/year). (2) The development of aquaculture was unbalanced in the space, and Wenchang City in the northeast of Hainan Island accounted for 47.87% of the total aquaculture area in 2018. The aquaculture centroids moved from the center of Hainan Island to the northeast with a total migration distance of 72.9 km from 1987 to 2018. (3) There were three different types of development tendencies in the coastal cities (counties) (aquaculture areas increased continually; aquaculture areas increased first and then decreased slightly; aquaculture areas increased first, and then decreased significantly), mainly related to the different regional characteristics and development orientations. The different evolution phases of coastal aquaculture in Hainan Island were driven by relevant national and local government policies. Formulating and implementing appropriate aquaculture policies according to local conditions, as well as promoting industrial upgrading of aquaculture with high-tech, are significant suggestions for sustainable aquaculture. This study provides baseline data for local managers to assess the development of coastal aquaculture and reference experiences of sustainable aquaculture for other tropical islands and countries. [Display omitted] • Mapping the coastal aquaculture and studying the spatio-temporal patterns of coastal aquaculture. • The coastal aquaculture first increased rapidly, then increased slowly, and then decreased slightly in the past 30 years. • Three different types of development tendencies in the coastal cities (counties) due to different orientations. • The development of coastal aquaculture were driven by relevant national and local government policies. [ABSTRACT FROM AUTHOR]